"use client";

import { useState, useEffect, useCallback } from "react";
import { createPortal } from "react-dom";
import { X, CheckCircle, Send, Phone as PhoneIcon, Instagram } from "lucide-react";
import { BRAND } from "@/lib/constants";

interface SignupModalProps {
  open: boolean;
  onClose: () => void;
  title?: string;
  subtitle?: string;
  /** API endpoint to POST to */
  endpoint: string;
  /** Extra fields merged into the POST body (e.g. masterClassTitle, classId, eventId, groupInfo) */
  extraBody?: Record<string, unknown>;
  /** Custom success message */
  successMessage?: string;
  /** Callback with API response data on success */
  onSuccess?: (data: Record<string, unknown>) => void;
}

export function SignupModal({
  open,
  onClose,
  title = "Записаться",
  subtitle,
  endpoint,
  extraBody,
  successMessage,
  onSuccess,
}: SignupModalProps) {
  const [name, setName] = useState("");
  const [phone, setPhone] = useState("+375 ");
  const [instagram, setInstagram] = useState("");
  const [telegram, setTelegram] = useState("");
  const [submitting, setSubmitting] = useState(false);
  const [error, setError] = useState("");
  const [success, setSuccess] = useState(false);
  const [successData, setSuccessData] = useState<Record<string, unknown> | null>(null);

  function handlePhoneChange(raw: string) {
    let digits = raw.replace(/\D/g, "");
    if (!digits.startsWith("375")) {
      digits = "375" + digits.replace(/^375?/, "");
    }
    digits = digits.slice(0, 12);
    let formatted = "+375";
    const rest = digits.slice(3);
    if (rest.length > 0) formatted += " (" + rest.slice(0, 2);
    if (rest.length >= 2) formatted += ") ";
    if (rest.length > 2) formatted += rest.slice(2, 5);
    if (rest.length > 5) formatted += "-" + rest.slice(5, 7);
    if (rest.length > 7) formatted += "-" + rest.slice(7, 9);
    setPhone(formatted);
  }

  useEffect(() => {
    if (!open) return;
    function onKey(e: KeyboardEvent) {
      if (e.key === "Escape") onClose();
    }
    document.addEventListener("keydown", onKey);
    return () => document.removeEventListener("keydown", onKey);
  }, [open, onClose]);

  useEffect(() => {
    if (open) document.body.style.overflow = "hidden";
    else document.body.style.overflow = "";
    return () => { document.body.style.overflow = ""; };
  }, [open]);

  const handleSubmit = useCallback(async (e: React.FormEvent) => {
    e.preventDefault();
    setError("");

    const cleanPhone = phone.replace(/\D/g, "");
    if (cleanPhone.length < 12) {
      setError("Введите корректный номер телефона");
      return;
    }

    setSubmitting(true);
    try {
      const body: Record<string, unknown> = {
        name: name.trim(),
        phone: cleanPhone,
        ...extraBody,
      };
      if (instagram.trim()) body.instagram = `@${instagram.trim()}`;
      if (telegram.trim()) body.telegram = `@${telegram.trim()}`;

      const res = await fetch(endpoint, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(body),
      });
      const data = await res.json();
      if (!res.ok) {
        setError(data.error || "Ошибка при записи");
        return;
      }
      setSuccess(true);
      setSuccessData(data);
      onSuccess?.(data);
    } catch {
      setError("network");
    } finally {
      setSubmitting(false);
    }
  }, [name, phone, instagram, telegram, endpoint, extraBody, onSuccess]);

  const handleClose = useCallback(() => {
    onClose();
    setTimeout(() => {
      setName("");
      setPhone("+375 ");
      setInstagram("");
      setTelegram("");
      setError("");
      setSuccess(false);
      setSuccessData(null);
    }, 300);
  }, [onClose]);

  function openInstagramDM() {
    const text = `Здравствуйте! Меня зовут ${name}. Хочу записаться${subtitle ? ` (${subtitle})` : ""}. Мой телефон: ${phone}`;
    window.open(`https://ig.me/m/blackheartdancehouse?text=${encodeURIComponent(text)}`, "_blank");
    handleClose();
  }

  if (!open) return null;

  return createPortal(
    <div className="modal-overlay fixed inset-0 z-50 flex items-center justify-center p-4" role="dialog" aria-modal="true" aria-label={title} onClick={handleClose}>
      <div className="absolute inset-0 bg-black/70 backdrop-blur-sm" />
      <div
        className="modal-content relative w-full max-w-md rounded-2xl border border-white/[0.08] bg-[#0a0a0a] p-6 sm:p-8 shadow-2xl"
        onClick={(e) => e.stopPropagation()}
      >
        <button
          onClick={handleClose}
          aria-label="Закрыть"
          className="absolute right-4 top-4 flex h-8 w-8 items-center justify-center rounded-full text-neutral-500 transition-colors hover:bg-white/[0.06] hover:text-white cursor-pointer"
        >
          <X size={18} />
        </button>

        {success ? (
          <div className="py-4 text-center">
            <div className="mx-auto mb-4 flex h-14 w-14 items-center justify-center rounded-full bg-emerald-500/10">
              <CheckCircle size={28} className="text-emerald-500" />
            </div>
            <h3 className="text-lg font-bold text-white">
              {successMessage || "Вы записаны!"}
            </h3>
            {subtitle && <p className="mt-1 text-sm text-neutral-400">{subtitle}</p>}
            {successData?.totalBookings !== undefined && (
              <p className="mt-3 text-sm text-white">
                Вы записаны на <span className="text-gold font-semibold">{String(successData.totalBookings)}</span> занятий.
                <br />
                Стоимость: <span className="text-gold font-semibold">{String(successData.pricePerClass)} BYN</span> за занятие
              </p>
            )}
            <button
              onClick={handleClose}
              className="mt-6 rounded-full bg-gold px-6 py-2.5 text-sm font-semibold text-black transition-all hover:bg-gold-light cursor-pointer"
            >
              Закрыть
            </button>
          </div>
        ) : error === "network" ? (
          /* Network error — fallback to Instagram DM */
          <div className="py-4 text-center">
            <div className="mx-auto mb-4 flex h-14 w-14 items-center justify-center rounded-full bg-amber-500/10">
              <Instagram size={28} className="text-amber-400" />
            </div>
            <h3 className="text-lg font-bold text-white">Что-то пошло не так</h3>
            <p className="mt-2 text-sm text-neutral-400">
              Не удалось отправить заявку. Свяжитесь с нами через Instagram — мы запишем вас!
            </p>
            <button
              onClick={openInstagramDM}
              className="mt-5 flex w-full items-center justify-center gap-2 rounded-xl bg-gradient-to-r from-purple-600 to-pink-500 py-3 text-sm font-semibold text-white transition-all hover:opacity-90 cursor-pointer"
            >
              <Instagram size={16} />
              Написать в Instagram
            </button>
            <button
              onClick={() => setError("")}
              className="mt-2 text-xs text-neutral-500 hover:text-white transition-colors cursor-pointer"
            >
              Попробовать снова
            </button>
          </div>
        ) : (
          <>
            <div className="mb-6">
              <h3 className="text-xl font-bold text-white">{title}</h3>
              {subtitle && <p className="mt-1 text-sm text-neutral-400">{subtitle}</p>}
            </div>

            <form onSubmit={handleSubmit} className="space-y-3">
              <input
                type="text"
                value={name}
                onChange={(e) => setName(e.target.value)}
                placeholder="Ваше имя"
                required
                className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] px-4 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
              />
              <div className="relative">
                <PhoneIcon size={14} className="absolute left-3 top-1/2 -translate-y-1/2 text-neutral-500" />
                <input
                  type="tel"
                  value={phone}
                  onChange={(e) => handlePhoneChange(e.target.value)}
                  placeholder="+375 (__) ___-__-__"
                  required
                  className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] pl-9 pr-4 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
                />
              </div>
              <div className="grid grid-cols-2 gap-2">
                <div className="relative">
                  <span className="absolute left-3 top-1/2 -translate-y-1/2 text-neutral-500 text-xs">@</span>
                  <input
                    type="text"
                    value={instagram}
                    onChange={(e) => setInstagram(e.target.value.replace(/^@/, ""))}
                    placeholder="Instagram"
                    className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] pl-7 pr-3 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
                  />
                </div>
                <div className="relative">
                  <span className="absolute left-3 top-1/2 -translate-y-1/2 text-neutral-500 text-xs">@</span>
                  <input
                    type="text"
                    value={telegram}
                    onChange={(e) => setTelegram(e.target.value.replace(/^@/, ""))}
                    placeholder="Telegram"
                    className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] pl-7 pr-3 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
                  />
                </div>
              </div>

              {error && error !== "network" && (
                <p className="text-sm text-red-400">{error}</p>
              )}

              <button
                type="submit"
                disabled={submitting}
                className="flex w-full items-center justify-center gap-2 rounded-xl bg-gold py-3 text-sm font-semibold text-black transition-all hover:bg-gold-light hover:shadow-lg hover:shadow-gold/20 cursor-pointer disabled:opacity-50"
              >
                <Send size={15} />
                {submitting ? "Записываем..." : "Записаться"}
              </button>
            </form>
          </>
        )}
      </div>
    </div>,
    document.body
  );
}